Resistance device



Oct 31, 1933. LI E I 1,932,923

RESI STANCE DEVICE Filed Nov. 15, 1950 Patented a. 31, 1933 1,932,923 7 nesrs'rancs DEVICE Frederic H.'Bullinger, Bronxville, N. Y; assignmto Ward Leonard Electric Company. a corporation of New York Application November 15, 1930 Serial No. 49,5,830 v Claims. (01. 20144) This application which relates not only to an improvement in resistance'devices, but also an improved method of making the same, applies particularly to that type of resistance device 5 wherein a resistive conductor is connected to one or more terminals and, more particularly, to such devices where the resistive conductor is covered by an insulating coating, or embedded thereby.

In resistance devices of this character, it is very important that the electrical connection between the resistive conductor and the terminals, taps, or contacts, shouki' be perfectly formed, and dependable in future long-continued use of the device. It is also important that the connection should be such that the process of manufacturing the resistance device will not impair the electrical connection, or strain, or loosen the resistive conductor. It is further important to provide a form of construction which will permit and insure all parts lying closely to the supporting element, so that the insulating coating will wellcover and protect the parts from deterioration and mechanical injury and to give, as far as possible, a smooth surface appearance.

' The main object of the present invention is to fulfill the above requirements and provide an improved resistance device and method of making which 'will be economical in cost of manufacture and well adapted for commercial pr'o-. Another object is to duction on a large scale. reduce to a minimum, or eliminate entirely, the number of defective devices produced'during the course of manufacture, as regards the electrical connection between the terminals and the resistive conductor, or breakage of the conductor at, or near, the terminal connections. Another object is to produce a form of construction and method of making, wherein the high temperature due to firing for maturing the insulating coating, such as when a vitreous enamel coating is used,

will not affect the electrical connection between in development, the particular form of terminal used in this instance; Fig. 5 is a side view of the unit after a further step in the process; and Fig. 6 is a side view of the completed unit.

The-insulating support in this instance is shown as a tube 1 of porcelain. The tube supports the variousterminals 2, three being shown in this instance, one an intermediate terminal, although obviously as many of these terminals as desired'may be used for the particular purpose intended. As shown by the development in Fig. 4; the terminals are formed in this instance from sheet metal and are in the form of a long strip having a perforation or slot 2a at one end provided for convenient connection to .an external circuit. A mid-portion of the strip has a cut-away portion, except as to a projection 2b. This projecting element has indentatidns 2c opposite each other at the outer part and is connected with the main portion of the strip by a narrow part or neck 2d. The slot 2c in the strip is provided in a portion which encircles the tube and is for the purpose of permitting the insulating coating to enter therethrough andcome in contact directly with the insulating support so as to more firmly hold the strip to the support. The holes 2) are for.the purpose of receiving the rivet 2g when the terminal is encircled about the tubular support so as to hold the same in place, the strip being bent along the dot and dash lines indicated in Fig. 4 where the end portions come together to be fastamed by the rivets, or any other securing means. Before application to the tubular support, the projections 2b of the terminals are bent outwardly at the neck 2d so as to project away therefrom. Thus, Figs. 1, 2 and 3 show these projections extending outwardly from the body of the unit and substantially at right angles thereto.

The terminals being mounted upon and secured to the insulating support 1, as already described, the conductor is connected thereto and applied as indicated in'Fig. 1. Starting at the left hand terminal where the conductor passes to the right from the terminal, one end of the conductor is first wound around the projection 2b in the indentations 20, giving the conductor one or more turns and is then passed under the neck 2d, and then passes over a portion of the terminal and around the insulating support with the desired number of turns to the next terminal. There the conductor is first passed around the neck 2d of the intermediate terminal and then around the duterportiumottheproiectionintheinden terminalandresistiveeonduetorwiththe Atthe expensive. Ahn'therobiectionmultln'mnthe II W w W W n u mmmmm fimm we 1m mmmmm m e m .m w n c immersedinthe material of hich temperature, and at then m mm described with reference projections 21; only are W m m oltenhiahiuainz soldering these are one line a indica wing lllottheaolderediointsmfl one time by immerainl the venom mmmmmm Wmmm e n a mmmm m m w mmmmmm N e W We mm 52% e Exam.

mm m m m em a the re'listive conductor is olten portiomotthereaiativedeviee relisteneedevieehaa m mm Mm w m m w m W W M m m M m M m m W m i new harm: on the mob-- eonductor and the projections 2b, a indicated 1N lbuellterhelitmwuflly mm.nnlmvreeinh u impcludwnntheeturneu the m M A mm wzmaw mm wm 3 m m W E? meme WWW mmmmwm wummnmuflmmm mmm m mmw Wm ,mwmmmm mm mm mg mdmmmmmmmm mmmw mm mmm m mmw mmmm Mmmmmw wdmmmm m mmzmm mmfimwmm ew m mmfi m Mm emm m m m um mwmw m tm m m mmw H mm a; rem e E m ?J53. J M i M m m 3?: m ewe e mi particular requirements and preference of the designer.

I claim:

1. The method of making a resistance device which comprises applying the resistive conductor and terminals to an insulating support and connecting the resistive conductor to projections outwardly extending from the terminals, immersing the projections only in a high temperature soldering bath, bending the projections toward the support, applying insulating coating material, and maturing the coating at a temperature lower than the soldering temperature.

2. The method 01' making a resistance device which comprises forming projections on the terminals with narrow portions connecting the projections to the main portions and having indented outer portions, applying the terminals and resistive conductor to a support and guiding the conductor around said narrow portions where it approaches or leaves the terminals and wrapping it around the indented outer portions of said projections, and soldering the connections at the outer portions of the projections.

3. The method of making a resistance device which comprises forming projections on the terminals with narrow portions connecting the projections to the main portions, applying the terminals and resistive conductor to a support and guiding the conductor around said narrow portions where it approaches or leaves the terminals and wrapping it around the outer portions of said projections, soldering the connections at the outer portions of the projections at high temperature, bending the projections toward the support, applyin insulating coating material, and maturing the coating at a temperature lower than the soldering temperature.

4. The method of making a resistance device which comprises forming projections on the terminals with narrow portions connecting the projections to the main portions, applying the terminals and resistive conductor to a support and guiding the conductor around said narrow portions where it approaches or leaves the terminals and wrapping it around the outer portions of said projections, immersing the projections only in a high temperature soldering bath, bending the projections toward the support, applying insulating coating material, and maturing the coating at a temperature lower than the soldering temperature. v

5. A resistance device comprising an insulat- 1:; support, a terminal mounted thereon, said terminal having a projection connected with said terminal by a narrow neck portion, the outer portion of said projection being indented, and a resistive conductor on said support passing close to said support around said neck portion and then around the indented outer portion of said projection for forming the connection be tween the conductor and the projection, the said connection being soldered,

FREDERIC H. BULLINGER. 

